Two high court judges were asked to decide "what is football?" after neighbours fell out over a kick-about in an exclusive, residents-only garden.
Christopher Fleming-Brown, 46, from Kensington, west London, was taken to court by Paula Lawton, 63, after playing ball with his son, aged five.
She accused him of turning the lawn garden into a recreation ground and breaching local by-laws.
Magistrates dismissed Ms Lawton's claim but she is challenging their ruling.
Retrial 'inappropriate'
The case concerned the alleged breach of by-laws governing the Arundel and Elgin gardens in the area close to Notting Hill.
Last November West London Magistrates said the banker's kick-abouts with his son did not amount to football in the eyes of the law.
She successfully challenged the magistrates' ruling before two senior judges at the High Court on Wednesday but was denied a retrial.
Lord Justice Waller, sitting with Mr Justice Treacy, said: "We think the justices took too narrow a view of what constituted football or a similar game by paying too much attention to the dictionary definition, which referred to two teams seeking to put the ball into the opposition's goal.